Recording galvanometer



Feb. 28, 1928. 1,660,921

R. FISCHER RECORDING GALVANOMETER Filed May 4. 1921 3 t 1 Fig.1

Febo 28, 1928. 1,660,921

R. FISC H ER REC ORDI NG GALVANOMETER Filed May 4, 1921 s Sheets-Sheet 2 Feb. 28, 1928. 1,660,921

R. FXSCHER RECORDING GALVANOMETER Filed May 4, 1921 3 Sheets-Sheet;

Fig.4

7 lFO EUD H UIDM Fig.5

Patented Feb. 28, 1928.

UNITED'STATES PATENT OFFICE.

RICHARD FISCHER, OF FRANKFORT-ON-THE-MAIN, GERMANY, ASSIGNOR TO THE FIRM F HARTMANN & BRAUN AKTIENGESELLSGHAFT, OF TRANKFORT-ON-THE- MAIN, GERMANY.

RECORDING GALVAN'OMETER.

Application filed May 4, 1921, Serial No. 466,712, and in Germany April 21, 1920.

This invention relates to that kind of recording galvanometers which are adapted to concurrently produce upon the same strip or chart records or diagrams in several colors corresponding to .several .electric currents. Such galvanometers are used' for instance to obtain records of a plurality of thermocouples or pyrometers installed at several remote places by means of one single instrument.

The principal diificulty to overcome in designing such apparatus is to render such diagrams easily distinguishable by the use of different colors and my invention has for its object to enable such diagrams to be produced by a single apparatus in such a manner that the colors are not mixed together and the records appear always fresh and clean on the strip.

The device designed for that purpose is represented in the accompanying drawings by way of example in the application to a pyrometer plant, but of course I do not wish to restrict myself to this application. It will be understood also that for the sake of clearness only such parts of the apparatus are represented which are required to render the invention comprehensible.

Fig. 1 is a side elevation of the recording apparatus as viewed from the right side of the machine.

Figures 2 and 3 show a special arrangement of the colored ribbons and Fig. 2 and Fig. 2 show details of the ribbon roll and clamping device respectively.

Fig. 4 gives by way of example the representation of the recording apparatus in conjunction with a number (6) of pyrometers, a casing for the recording apparatus being designated by dotted lines, while the recording apparatus parts and the various circuits are indicated in unbroken lines.

Fig. 5 illustrates a portion of the recording strip as it passes from the apparatus; of course the records should be understood to be in different colors.

Fig. 6 is a perspective view of-theribbon carrying frame showing the arrangement of the ribbons thereon.

Fig. 7 is an enlarged detail view showin the initial position of the shiftable ribbon frame with the first ribbon in printing position, and

Fig. 8 is an enlarged detail View similar to Fig. 7 but showing the ribbon frame shifted to its extreme or furtherest point, in which position the last or sixth ribbon is in printing position.

As will be seen from Fig. 5 the individual curves partially intersect one another. They are obtained through the edge-shaped portion 2 of the pointer 5 of a galvanometer system being automatically pressed down against a colored ribbon which extends longitudinally beneath the marker, leaving each time a colored mark on the surface of the paper. p

The means by which the pointer is pressed down is generally known and does not form an object of my invention. Nevertheless, only for the sake of better comprehension, I wish to describe the active parts of the apparatus in connection with my invention and with reference to the drawings.

In Fig. 1, 3 is a permanent magnet between the poles of which a coil 4 is moved under the influence of the current to be measured, whereby the knife-edged end 2 of the pointer 5 is caused to sweep in the arc of a circle to a degree corresponding to the actual intensity of the current. The recording strip 1 is wound on a feeder roller 6 in the known manner, then led over aroller of a relatively smalldiameter which forms the chord of the are described by the knifeedge 2 of the pointer. It runs farther over a roller 8 to the pegged cylinder 9 which in the known manner engages with the perforations provided in the strip. The cylinder is driven by the time mechanism 10 by means of gear-wheels 11 and the lever 12' is moved downwards every 30 seconds by the clock-work, as indicated by the arrow. The lever 12 may be operated by means of a cam 51, theaxis of which is turned continuously by the clock work 10. This cam bears against the roller 52 fixed onto the lever 12 and lifts the latter up to its upper position. As soon as roller 52 passes from the high part of the cam the lever 12 falls to the dotted line position shown in Fig. 1. As the axis of the cam continues torotate, the cam acts on the roller 52 and the lever 12 is again lifted up and so on, so that the said lever is moved periodically up and down. This periodic movement of the lever 12 may be accomplished in any other well known way without changing the spirit of the present invention.

' As mentioned above the records are obtained by 'means of colored ribbons interposed between the record strip and the pointer. Tn the example shown ll'have de-, signed 6 ribbons of different colors, f. i. red, green, blue, brown, black and purple, which are shown diagrammatically in Fig. 6. These ribbons are arranged on a frame formed by the axis v22 and the end plates 23, 24: inthe shape of a of 90.

The segment 232 l is adapted to be moved step by step to bring the successive ribbons, one at a time, into operating position between the marking device 2 and the receiving strip 1. A mutilated gear rotated with the ratchet 26 provides for the return of the segment to initial position when the final ribbon in the series has taken part in a marking operation.

The ratchet 26 also serves to operate the switch or brush 29 which is moved from contact to contact to establish a new pyrometer circuit with each successive step in the operation of moving colored ribbons into marking position.

Through the aforementioned downward movement of the lever 12 two principal actions are brought about viz: (see Fig. 2). (1) The movable frame 15 pivoted at 14 is moved downwardly by means of the lever arm 13, pressing down simultaneously the knife-edge 2 of the elastic pointer 5;

(2) The pawl 25 engages with the next tooth of the ratchet 26.

By choosing the proper ratio of transformation the frame carrying the ribbons is intermittently advanced under the marker until all of the ribbons have passed. Then, by means of gravity acting through the counter-weight 50 on the shaft 22, the frame reverts from the end position shown in Figure 2 into its initial position.

To better understand the shifting or pro-' 'ressive advancement of the ribbon carryinggframe to successlvely present the r1bbons 1 to 6 reference-is now made to theillustrations of Figs. 7 and 8. lln lBig. 7 the ribbon frame is in its initial position with ribbon 1 in active position, while Fig.

8 illustratesthe frame in its final position with the 6th ribbon properly positioned When as shown in Fig. 7, the pawl 25 is given an upward thrust its engagement with the ratchet wheel 26 will advance the gear and the cooperating sector one-sixth of a i the last or sixth ribbon turn, bringing the second ribbon into position. The next operation of the pawl '25 shifts the parts another one-sixth, bringing the third ribbon into active position. These successive advancements are continued until is in printing position and the parts will then be as shown in cylindrical segment .ment shown in Fig.

neeoeai six positions of the gear which will cause the progressive advancement of the six printing ribbons.

Through the action of the ratchet 26 an electric commutator 27 for e. g. six difierent circuits is operated. The manner in which the six thermometers are successively inserted in the circuit is clearly shown in Fig. 4., although these particulars do not belong to the essential feature of my invention.

' When the knife-edged pointer 2 is pressed successively upon six bons it will of course take every time a bit of color from each of them and since on account of the small power available for producing the marks on the strip the ribbon must be kept rather humid it ensues from the foregoing that the pointer will gradually transmit the color from one ribbon to another so that after a fewdays use the colors will be mixed and the ribbons become unfit for producing clear and distinct marks on the paper.

To overcome this inconveniencel provide the ribbonswith a thin protective cover of any moisture-proof material, such as gutta percha or the like. Tn Figs. 2 and 3 this arrangement is clearly shown, wherein 16 is the ribbon and 37 the protective cover or guard which, in reality, is so thin that it is rather difficult to be represented and in the other figures is done away with, except in Fig. 6. It is preferable to wind the guard together with the ribbon onthe same roller 4:3.

Since the arrangementon either side of the frame of six rollers of that kind would meet with dificulties, Tprefer the arrange- 6, where three rollers with their guards and three clamping devices are alternately attached to either side of the frame.

Fig. 2 illustrates some details of the clamping device. It will be seen that the ribbon is wound on one side only on the differently colored riblltl roller 43, whilst on the other side it 15 led through the recess 44 of the slide clamp 45. When the latter is lifted the clamp is loosened and the worn out piece of the rib bon may bepulled out.

Although I prefer the arrangement above described of'a guard of gutta percha or a similar material interposed between the pointer and the colored ribbon, T do not wish to restrict myself thereto, since the ribbon itself may as well be covered with a layer of varnish or metal or any other suitable material.

- Now what I claim is:

In an apparatus for recording characteristics of a plurality of electrical circuits, a record receiving surface, a marking device movable toward and from the surface and laterally along the surface, a plurality of inked ribbons of diiferent colors, an arcuate segment for supporting said ribbons, means responsive to the characteristics of the circuits for determining the lateral position of the marking device, means for connecting the electrically responsive means in succession of the plurality of circuits, means for moving the arcuate segment step-by-step in accordance with the successive circuit connections to bring the series of colored inked ribbons one at a time into position between the marking device and the surface, and means "for operating the marking device! In testimony whereof I have afixed my 20 signature.

RICHARD FISCHER. 

